Process for the production of a pressure-sensitive carbonless copy sheet using microcapsules formed in situ in a radiation curable binder

Abstract

A process is provided for the production of a coating composition containing microcapsules having a hydrophilic core for use in the manufacture of pressure-sensitive carbonless transfer papers comprising the following steps. A hydrophilic emulsion component is prepared by dispersing at least one chromogenic material being soluble in the hydrophilic liquid. A hydrophobic emulsion component is prepared by dispersing an emulsifier in a radiation curable hydrophobic liquid. A first wall-forming material and a second wall-forming material are added to the hydrophobic emulsion component, with mixing. The first and second wall-forming materials are soluble in the hydrophobic emulsion component, and the first wall-forming material is reactive with the second wall-forming material to form a polymeric capsule wall. The resultant polymeric capsule wall is substantially insoluble in the hydrophilic and the hydrophobic emulsion components. The hydrophobic emulsion component is mixed together with the hydrophilic emulsion component to form an emulsion containing droplets of the hydrophilic emulsion component dispersed in the hydrophobic emulsion component. Mixing is maintained for a period of time sufficient to allow the first and second wall-forming materials to react to form a dispersion of microcapsules in the hydrophobic emulsion component. The formed microcapsules have capsule walls substantially impermeable to the hydrophobic and the hydrophilic emulsion components. Pressure-sensitive carbonless transfer paper may be produced by applying the dispersion of the microcapsules prepared as above to a substrate, and curing the dispersion by subjecting the dispersion on the substrate to radiation for a period of time sufficient to cure the radiation curable hydrophobic liquid, thereby producing a tack-free, resinous film on the substrate.

What is claimed is: 
     
       1. A process for producing a liquid substantially solvent-free coating composition for use in the manufacture of pressure-sensitive carbonless transfer papers, said liquid coating composition being characterized by being radiation curable by polymerization to a dry, solid, tack-free resin substantially without the removal of solvents and other liquids and being further characterized by containing microcapsules having a hydrophilic core material, comprising the steps of: (a) preparing a liquid hydrophilic emulsion component by dispersing at least one chromogenic material in a hydrophilic liquid, said chromogenic material being soluble in said hydrophilic liquid;   (b) preparing a liquid hydrophobic emulsion component by dispersing an emulsifier in a radiation curable hydrophobic liquid;   (c) adding to said liquid hydrophobic emulsion component, with mixing, a first wall-forming material and second wall-forming material, said first and second wall-forming materials being soluble in said liquid hydrophobic emulsion component, said first wall-forming material being reactive with said second wall-forming material to form a polymeric capsule wall, said polymeric capsule wall being substantially insoluble in said liquid hydrophilic and said liquid hydrophobic emulsion components;   
     
     
       (d) mixing said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component to form an emulsion containing droplets of said liquid hydrophilic emulsion component dispersed in said liquid hydrophobic emulsion component; and 
     
     
       (e) maintaining said mixing for a period of time sufficient to allow said first and second wall-forming materials to react to form a dispersion of microcapsules in said liquid hydrophobic emulsion component, said microcapsules having capsule walls substantially impermeable to said liquid hydrophobic and said liquid hydrophilic emulsion components. 
     
     
       2. The process of claim 1 wherein said first and second wall-forming materials are added to said liquid hydrophobic emulsion component after said mixing of said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component. 
     
     
       3. The process of claim 1 wherein said radiation curable hydrophobic liquid comprises at least one ethylenically unsaturated organic compound having at least one terminal ethylenic group per molecule. 
     
     
       4. The process of claim 1 wherein said first wall-forming material is a member of the group consisting of polyols, polythiols, polyamines, acid anhydrides, polycarboxylic acids, and epoxy compounds and said second wall-forming material is a polyisocyanate. 
     
     
       5. The process of claim 4 wherein said first wall-forming material is a polyol. 
     
     
       6. The process of claim 1 wherein said chromogenic material is a color former selected from the group consisting of ammonium ferric sulfate, ferric oleate, sodium orthovanadate, ammonium metavanadate, ferric sulfate, cupric sulfate, cupric oleate and mixtures thereof. 
     
     
       7. The process of claim 1 wherein a catalyst capable of promoting the reaction of said first wall-forming material with said second wall-forming material is added to said emulsion prior to the reaction of said first wall-forming material with said second wall-forming material. 
     
     
       8. A process for producing a liquid substantially solvent-free coating composition for use in the manufacture of pressure-sensitive carbonless transfer papers, said liquid coating composition being characterized by being radiation curable by polymerization to a dry, solid, tack-free resin substantially without the removal of solvents and other liquids and being further characterized by containing microcapsules having a hydrophilic core material, comprising the steps of: (a) preparing a liquid hydrophilic emulsion component by dispersing at least one chromogenic material in a hydrophilic liquid, said chromogenic material being soluble in said hydrophilic liquid;   (b) preparing a liquid hyrophobic emulsion component by dispersing an emulsifier in a first portion of a radiation curable hydrophobic liquid, said liquid hydrophobic emulsion component having a viscosity from about 1 centipoise to about 500 centipoise, said radiation curable hydrophobic liquid comprising at least one ethylenically unsaturated organic compound having at least one terminal ethylenic group per molecule;   (c) adding to said liquid hydrophobic emulsion component, with mixing, at least one polyol and at least one polyisocyanate, said polyol and said polyisocyanate being soluble in said liquid hydrophobic emulsion component, said polyol being reactive with said polyisocyanate to form a polymeric capsule wall, said polymeric capsule wall being substantially insoluble in said liquid hydrophilic and said liquid hydrophobic emulsion components;   (d) mixing said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component to form an emulsion containing droplets of said liquid hydrophilic emulsion component dispersed in said liquid hydrophobic emulsion component;   (e) maintaining said mixing for a period of time sufficient to allow said polyol and said polyisocyanate to react to form a dispersion of microcapsules in said liquid hydrophobic emulsion component, said microcapsules having capsule walls substantially impermeable to said liquid hydrophobic and said liquid hydrophilic emulsion components; and   (f) adding to said dispersion of said microcapsules in said liquid hydrophobic emulsion component a second portion of a radiation curable hydrophobic liquid, said second portion including at least one ethylenically unsaturated organic compound having more than one terminal ethylenic group per molecule.   
     
     
       9. The process of claim 8 wherein a photoinitiator is added to said dispersion of microcapsules. 
     
     
       10. A process for producing a liquid substantially solvent-free coating composition for use in the manufacture of pressure-sensitive carbonless transfer papers, said liquid coating composition being characterized by being radiation curable by polymerization to a dry solid, tack-free resin substantially without the removal of solvents and other liquids and being further characterized by containing microcapsules having a hydrophilic core material, comprising the steps of: (a) preparing a liquid hydrophilic emulsion component by dispersing at least one chromogenic material in a hydrophilic liquid, said chromogenic material being soluble in said hydrophilic liquid;   (b) preparing a liquid hydrophobic emulsion component by dispersing an emulsifier in a first portion of a radiation curable hydrophobic liquid, said liquid hydrophobic emulsion component having a viscosity from about 1 centipoise to about 500 centipoise, said radiation curable hydrophobic liquid comprising at least one ethylenically unsaturated organic compound having at least one terminal ethylenic group per molecule;   (c) mixing said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component to form an emulsion containing droplets of said liquid hydrophilic emulsion component dispersed in said liquid hydrophobic emulsion component;   (d) adding at least one polyol and at least one polyisocyanate to said liquid hydrophobic emulsion component with further mixing, said polyol and said polyisocyanate being soluble in said liquid hydrophobic emulsion component, said polyol being reactive with said polyisocyanate to form a polymeric capsule wall, said polymeric capsule wall being substantially insoluble in said liquid hydrophilic and said liquid hydrophobic emulsion components;   (e) maintaining said mixing for a period of time sufficient to allow said polyol and said polyisocyanate to react to form a dispersion of microcapsules in said liquid hydrophobic emulsion component, said microcapsules having capsule walls being substantially impermeable to said liquid hydrophobic and said liquid hydrophilic emulsion components; and   (f) adding to said dispersion of said microcapsules in said liquid hydrophobic emulsion component a second portion of a radiation curable hydrophobic liquid, said second portion including at least one ethylenically unsaturated organic compound having more than one terminal ethylenic group per molecule.   
     
     
       11. The process of claim 10 wherein a photoinitiator is added to said dispersion of microcapsules. 
     
     
       12. A process for producing a pressure-sensitive carbonless transfer paper comprising the steps of: (a) preparing a liquid hydrophilic emulsion component by dispersing at least one chromogenic material in a hydrophilic liquid, said chromogenic material being soluble in said hydrophilic liquid;   (b) preparing a liquid hydrophobic emulsion component by dispersing an emulsifier in a radiation curable hydrophobic liquid;   (c) adding to said liquid hydrophobic emulsion component, with mixing, a first wall-forming material and second wall-forming material, said first and second wall-forming materials being soluble in said liquid hydrophobic emulsion component, said first wall-forming material being reactive with said second wall-forming material to form a polymeric capsule wall, said polymeric capsule wall being substantially insoluble in said liquid hydrophilic and said liquid hydrophobic emulsion components;   (d) mixing said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component to form an emulsion containing droplets of said liquid hydrophilic emulsion component dispersed in said liquid hydrophobic emulsion component;   (e) maintaining said mixing for a period of time sufficient to allow said first and second wall-forming materials to react to form a dispersion of microcapsules in said liquid hydrophobic emulsion component, said microcapsules having capsule walls substantially impermeable to said liquid hydrophobic and said liquid hydrophilic emulsion components;   (f) applying said dispersion of said microcapsules to a substrate; and   (g) curing said dispersion of said microcapsules by subjecting said dispersion of said microcapsules on said substrate to radiation for a period of time sufficient to cure said dispersion of said microcapsules by polymerization of said radiation curable hydrophobic liquid, thereby producing a dry, solid, tack-free resinous film on said substrate substantially without the removal of solvents or other liquids.   
     
     
       13. The process of claim 12 wherein said first and second wall-forming materials are added to said liquid hydrophobic emulsion component after said mixing of said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component. 
     
     
       14. The process of claim 12 wherein said radiation curable hydrophobic liquid comprised at least one ethylenically unsaturated organic compound having at least one terminal ethylenic group per molecule. 
     
     
       15. The process of claim 12 wherein said first wall-forming material is a polyol and said second wall-forming material is a polyisocyanate. 
     
     
       16. The process of claim 12 wherein said chromogenic material is selected from the group consisting of ammonium ferric sulfate, ferric oleate, sodium orthovanadate, ammonium metavanadate, ferric sulfate, cupric sulfate, cupric oleate and mixtures thereof. 
     
     
       17. The process of claim 12 wherein a catalyst capable of promoting the reaction of said first wall-forming material with said second wall-forming is added to said emulsion prior to the reaction of said first wall-forming material with said second wall-forming material. 
     
     
       18. A process for producing a pressure-sensitive carbonless transfer paper comprising the steps of: (a) preparing a liquid hydrophilic emulsion component by dispersing at least one chromogenic material in a hydrophilic liquid, said chromogenic material being soluble in said hydrophilic liquid;   (b) preparing a liquid hydrophobic emulsion component by dispersing an emulsifier in a radiation curable hydrophobic liquid, said liquid hydrophobic emulsion component having a viscosity from about 1 centipoise to about 500 centipoise, said radiation curable hydrophobic liquid comprising at least one ethylenically unsaturated organic compound having at least one terminal ethylenic group per molecule;   (c) adding to said liquid hydrophobic emulsion component, with mixing, at least one polyol and at least one polyisocyanate, said polyol and said polyisocyanate being soluble in said liquid hydrophobic emulsion component, said polyol being reactive with said polyioscyanate to form a polymeric capsule wall, said polymeric capsule wall being substantially insoluble in said liquid hydrophilic and said liquid hydrophobic emulsion components;   (d) mixing said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component to form an emulsion containing droplets of said liquid hydrophilic emulsion component dispersed in said liquid hydrophobic emulsion component;   (e) maintaining said mixing for a period of time sufficient to allow said polyol and said polyisocyanate to react to form a dispersion of microcapsules in said liquid hydrophobic emulsion component, said microcapsules having capsule walls substantially impermeable to said liquid hydrophobic and said liquid hydrophilic emulsion components;   (f) applying said dispersion of said microcapsules to a paper substrate; and   (g) curing said dispersion of said microcapsules by subjecting said dispersion of said microcapsules on said paper substrate to radiation for a period of time sufficient to cure said dispersion of said microcapsules by polymerization of said radiation curable hydrophobic liquid, thereby producing a dry, solid, tack-free resinous film on said paper substrate substantially without the removal of solvents or other liquids.   
     
     
       19. The process of claim 18 wherein said radiation curable hydrophobic liquid comprises a mixture of ethylenically unsaturated organic compounds, a portion of said compounds having one terminal ethylenic group per molecule and another portion of said compounds having more than one terminal ethylenic group per molecule. 
     
     
       20. The process of claim 18 wherein a photoinitiator is added to said dispersion of microcapsules and said radiation is ultraviolet light. 
     
     
       21. A process for producing a pressure-sensitive carbonless transfer paper comprising the steps of: (a) preparing a liquid hydrophilic emulsion component by dispersing at least one chromogenic material in a hydrophilic liquid, said chromogenic material being soluble in said hydrophilic liquid;   (b) preparing a liquid hydrophobic emulsion component by dispersing an emulsifier in a radiation curable hydrophobic liquid, said liquid hydrophobic emulsion component having a viscosity from about 1 centipoise to about 500 centipoise, said radiation curable hydrophobic liquid comprising at least one ethylenically unsaturated organic compound having at least one terminal ethylenic group per molecule;   (c) mixing said liquid hydrophobic emulsion component with said liquid hydrophilic emulsion component to form an emulsion containing droplets of said liquid hydrophilic emulsion component dispersed in said liquid hydrophobic emulsion component;   (d) adding at least one polyol and at least one polyisocyanate to said liquid hydrophobic emulsion component with further mixing, said polyol and said polyisocyanate being soluble in said hydrophobic liquid, said polyol being reactive with said polyisocyanate to form a polymeric capsule wall, said polymeric capsule wall being substantially insoluble in said liquid hydrophilic and said liquid hydrophobic emulsion components;   (e) maintaining said mixing for a period of time sufficient to allow said polyol and said isocyanate to react to form a dispersion of microcapsules in said liquid hydrophobic emulsion component, said microcapsules having capsule walls substantially impermeable to said liquid hydrophobic and said liquid hydrophilic emulsion components;   (f) applying said dispersion of said microcapsules to a paper substrate; and   (g) curing said dispersion of said microcapsules by subjecting said dispersion of said microcapsules on said paper substrate to radiation for a period of time sufficient to cure said dispersion of said microcapsules, by polymerization of said radiation curable hydrophobic liquid, thereby producing a dry, solid, tack-free resinous film on said paper substrate substantially without the removal of solvents or other liquids.   
     
     
       22. The process of claim 21 wherein said radiation curable hydrophobic liquid comprises a mixture of ethylenically unsaturated organic compounds, a portion of said compounds having one terminal ethylenic group per molecule and another portion of said compounds having more than one terminal ethylenic group per molecule. 
     
     
       23. The process of claim 21 wherein a photoinitiator is added to said dispersion of microcapsules and said radiation is ultraviolet light. 
     
     
       24. The pressure-sensitive carbonless transfer paper produced by the process of claim 18. 
     
     
       25. The pressure-sensitive carbonless transfer paper produced by the process of claim 21.